7 Integrity Considerations When Sourcing Carbon Credits 

Not that long ago, buying a carbon credit seemed fairly straightforward, as were the claims you could make once purchasing that credit. But increasing public and journalistic scrutiny around carbon credits has seen the market respond with frameworks to strengthen their integrity.  

Examples include the Integrity Council for Voluntary Carbon Markets (ICVCM), which rates crediting programmes against ten Core Carbon Principles; and the Voluntary Carbon Markets Integrity Initiative (VCMI), which published a Claims Code of Practice that aims to guide buyers on how they can make – and talk about – their voluntary use of high-quality carbon credits as part of their climate commitments. 

Programmes like Gold Standard also publish documents on the kinds of claims to make, while independent ratings agencies like BeZero and Sylvera publish ongoing assessments rather than one-off approvals.  

Understandably, companies today want to know whether a credit – and the claim they make about it – holds up to that scrutiny. Here are seven reasons why meeting the carbon integrity bar requires careful vetting of carbon credits and the projects behind them.

1. Additionality is difficult to prove 

The first question behind every credit – and a foundational requirement in the Australian Government’s own ACCU Scheme – is whether the emissions reduction would have happened anyway. If a forest was never going to be logged, or a renewable project was already commercially viable without carbon finance, the credit isn’t adding anything new to the climate outcome.   

 2. Baselines are inconsistent and open to interpretation 

Even when a project is genuinely additional, the baseline used to calculate “avoided” emissions is often set on a per-project basis rather than against a consistent, independently verified benchmark.   

Baselines don’t have to be manipulated deliberately to be wrong; they just have to fail to account for conditions outside anyone’s control. Mitchell et al. (2024) examined a 2023 Clean Energy Regulator issuance of roughly 250,000 ACCUs from six grazing farms and found the credited soil carbon gains were measured during a period of exceptionally high rainfall across eastern Australia, well above the rates reported elsewhere in Australian scientific literature.  

Their analysis found the gains were largely attributable to rainfall rather than land management and the elevated sequestration rate wasn’t sustained once rainfall returned to average levels. 

3. Permanence can’t be guaranteed 

A credit sold today should represent a long-term reduction in atmospheric carbon, with low risk of that sequestration being reversed (and if reversal risk is higher, there should be safeguards in place to manage this). Nature-based projects may still be vulnerable to fire, drought, disease, logging and land-use change, and low or variable rainfall can make carbon stock gains harder to sustain over time.  

Australia’s scheme has a formal mechanism for this: under the Clean Energy Regulator’s permanence obligations, landholders can be issued a relinquishment notice requiring credits to be returned if stored carbon is released and reasonable preventive steps weren’t taken. 

International voluntary standards (like Verra’s Verified Carbon Standard Program) also have detailed mechanisms that project developers must follow in the event of a reversal, including requiring substantial ‘buffer’ credits, replacement credits, rectification, or immediate halting of the project. 

4. Double counting is a structural risk 

The same tonne of avoided or removed emissions could be claimed more than once: by the project developer, by the company that bought the credit and maybe by the host country counting it toward its own Nationally Determined Contributions (NDCs).   

Under the Paris Agreement’s Article 6, countries are meant to apply “corresponding adjustments” (in effect, double-entry bookkeeping between a selling and buying country) to prevent a credit being counted both by the buying company and by the host country toward its own NDCs. The mechanism works in principle, but it depends on host-country authorisation and consistent reporting, and some internationally transferred credits may still change hands without the adjustment being applied. 

This is precisely the gap the UN is now trying to close structurally. Development began in January 2026 on a dedicated Article 6.2 International Registry, built to centrally track, authorise and report Internationally Transferred Mitigation Outcomes (ITMOs) – the term used for an emissions reduction one country transfers to another to count towards its climate target – so that corresponding adjustments are enforced by infrastructure rather than left to individual countries’ reporting.

5. Standards are fragmented 

There’s no single global rulebook. Multiple crediting programmes and methodologies have historically operated with varying degrees of rigour, and third-party auditors differ in independence, site access and review quality. One response to this has come from the Integrity Council for the Voluntary Carbon Market (ICVCM) in the form of Core Carbon Principles.  

The CCP identifies ten science-based principles used for identifying high-integrity carbon credits, assessed through a formal Assessment Framework that checks whether a crediting programme and its methodologies meet criteria on quantification, additionality, permanence and monitoring. That’s a genuine improvement, but it’s a young classification and the majority of issued credits on the market do not conform to CCP-approved methodologies.

6. High-integrity supply can’t keep up with demand 

Durable, well-verified credits are limited relative to demand and the highest-rated among them, particularly removals, are priced accordingly. MSCI (2025), in its “State of Integrity in the Global Carbon-Credit Market” report, rated more than 4,400 registered projects and found fewer than one in ten reached its highest integrity band.  

That’s a narrow top tier within one ratings framework rather than a verdict on the wider pool of credible credits sitting just below it. But it does illustrate why organisations chasing volume or working to a tight budget can end up with a portfolio weighted toward the credits that are easiest to source, rather than the ones most likely to withstand scrutiny. 

This isn’t a static picture, either. Leading international voluntary standards have spent close to two decades refining their methodologies as monitoring science, remote sensing and baseline modelling have improved, and that ongoing tightening is part of why the bar for “high-integrity” keeps rising.

7. Transparency, social impact and shifting rules compound the risk 

Pricing, project documentation, broker incentives and secondary-market trading can be opaque, which makes due diligence harder than it should be. Layer on regulation that’s still catching up (climate disclosure standards increasingly require companies to explain how they use carbon credits, including information about the type of credits and factors affecting their credibility and integrity) and a credit considered acceptable a few years ago may not meet current expectations. Buyers can find themselves exposed to reputational risk even when they followed accepted practice at the time of purchase. 

The bottom line to sourcing credits 

All this considered, due diligence goes well beyond checking a registry logo. Look for projects that can demonstrate additionality with clear evidence, baselines set against independently verified benchmarks and monitoring that continues well past the point of sale.   

Favour crediting programmes assessed against a recognised integrity threshold, like the Core Carbon Principles, over those that simply issue the most credits. For credits tied to national climate targets (NDCs), check that the relevant corresponding adjustment has actually been applied.  

And most importantly, treat offsets as part of a climate portfolio whilst setting targets for absolute emissions reduction.  

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